Mercury switch relay



July 27, 1943. c. H. LARSON 2,325,186

MERCURY SWITCH RELAY Filed May 29, 1941 g I 26 INVENTOR. 0 BY CcZ/ZJ fi. la/zsofa ATTORNEYS.

Patented July 27, 1943 U -T f "STATES l PATENT orr ce Q 2,325,186 I I MERCURY SWITCH RELAY Carl H. Larson, Elkhart, Ind., assignor to The Adlake Company; a corporation of Illinois The principal object of my invention is to provide a compact and inexpensive mounting fo mercury switch relays and accessory apparatus. Other objects are to provide a mounting of the type described which may be easily formed by ordinary shop equipment from sheet material encloses the electric wiring and, some ofthe electrical equipment, may be easily dismounted for inspection and repair and which affords a maximum degree of. accessibility .to the mounted elements. I a

The attainment of these'and other objects and advantages will become apparent from the following disclosure and from the drawing, in

which a 1 Fig. 1 is a perspective view of my mounting with the cover removed; and 7 Fig.2 is a transverse and section of my assembledmounting. 1

In the embodiment illustrated and subsequently described, I have shown a mercury switch ofthe displacer type controlled by an external relay coil, which is energizedby a circuit including an amplifying tube to attainhigh sensiti-vityto small fluctuations in the energizing current, all or" the above elements being disposed on my improved mounting, but it is to be understood that other types of relays and associated controlling means. may be substituted for the above elements, or other controlling means andswitches added without departing from the scope and spirit of my invention. a a

' Referring tothejdrawing, in Fig. l I have shown a mounting.particularly'adapted for use in instances where a mercury switch relay 'H must respond to small fluctuations or impulses in the relay energizing current, as where the relay'controls the heating elements in a constant temperature bath and must respond to the low.

current transmitted by a thermostat. Sensitivity to thesesmall currents may be obtained by us ng an amplifier tube !2, such as tube No. 7'0L7 T manufactured by the, Ken Radv Tube and Lamp Corporation of ()wenjsb oro, Kentucky, to amplify the relay control current. I

Beth the tube-li and the mercury switch r lay ll may be conveniently"mounted upon a Z section, generally designated "l3, comprising a relatively high'baclr panel M, a floor panel h and terminal panel H. The terminal panel l7 and the back panel M extend l'at erally from the cndsof the'floor panel 16in oppositdirections perpendicularly thereto. The 2 section may be formed of "any desired sheet material by joiningt'ogethcr' three plates along their edges at right angles to each other or by bending a rec tangular sheet metal plate upon an ordinary brake, but due to economy, the latter method of construction is preferred, In forming the 2 section 13 the terminal panel I! is preferably made somewhat shorter than the back panel l4, but should extend downwardly beyond the accessory electrical apparatus l8 and wiring l9 disposed on, or adjacent to theunder side of the floor panel l5.

The under side of the floor panel I6 .is prefer-- ably covered with a thin sheet of insulatin material 2!, such as varnished cloth or fiber, which may be held in position by adhesive or by rivets 22 extending through the insulation and the 'fioor panel. A panel 23 of rigid insulating material, such as Bakelite, hard rubber, 0 the like, is attached to the front of the terminal panel 'I'! by screws 24. Binding posts are mounted on and extend through the panel 23, the panel being 'cut away, as indicated at 2?, to permit the passage of the binding without contact therewith. a

The mercury switch relay l I is of the displacer type and includes an envelope 28 containing a quantity of mercury, spaced contacts within the envelope, and a magnetically responsive displacer withinthe envelope adapted to shift the level of the mercury fill to bridge and unbridge the contacts in response to external magnetic force. The envelope 28 may besupported within a relay coil 29 by a rubber sleeve 30 .telescoped over the envelope 28 and having firm but resilient frictional engagement therewith. The lower end of the envelope 28 is. preferably providedwith a protective sleeve 3|, which may be formed of fiber or other suitable material and serves to protect the envelope and switch terminals which are sealed through the base of the switch. The coil 23 is provided witha Ushaped external iron circuit 32 rigid with the coil!!! and having a leg 33 substantially'parallel to the axis of the coil, the leg 33 being provided with tapped openings to receive mounting screws 34. A web 36 having a laterally extending end flange 40 is adjustably attached to the lower leg of the iron circuit 32 by a screw 37. The leg 40 extends upwardly into abutment with the iron circuit and the end of the web '36 opposite the leg 40 is cut away to at least partially encircle the switch envelope 23 adjacent the bottom surface of the rubber sleeve 31 The web 36 supports the rubber sleeve 30 and, if desired, may be employed to force the sleeve against the iron circuit 32, thereby *distortingthe sleeve wires 39. A tube base 4|, adapted to receive the tube H, is attached to the floor panel I6 by screws 42 over an opening in the floor panel through which contacts may extend to the under side of the panel.

These contacts are connected noted that it is impossible to remove the cover from the 2 section without dismounting the assembly as the cover attaching screws areinserted from the rear. This is often advantageous, as it prevents tampering or accidental removal of the cover. If desired, however, the cover attaching screws 46 may be inserted from the front of the back panel l4, thereby permitting removal of the cover 41 without removing the Z section from its support. In the latter instance, the openings 52 in the back of the cover are threaded, instead of the openings 44 in the back panel [4.

From the foregoing description it is apparent that due to the simplicity of my improved mountto the relay coil 29 by wires, generally desig-w hated I9, and through accessoryelectrical ap-I erally designated l8, as well as to terminal posts 26. V

The back panel l4 is provided with holes 43 to receive mounting screws by means of which the mounting may be attached to a vertical wall or other rigid upright support and is also provided with a plurality of tapped holes 44 adjacent the floor panel It to receive cover attachment screws 46. j

A cover, generally designated 41, is provided to enclose the wiring, the shape of the cover resembling a rectangular box having an open top and front. The cover 'may conveniently be formed from sheet metal on a brake or from other desired material in amanner similar to that described in connection with the 2 section,

and includes back .48 which extends upwardly beyond twoend walls 49 and has a height'greater than the depth of the terminal plate 23. The

back 48 and end walls 49 define a cover bottom 5! having a length and width substantially equal to the length and width of the floor panel Hi,

the height of the end walls 49 being such that when brought into abutment with the lower surface of thefioor panel l6, the bottom 5| of the coverwill be flush'with the lower edge of the terminal panel I1. If the cover 41 is formed from a relatively heavy gauge metal it has not been found necessary to provide any form of at- V tachrnent between the end walls 49 and the back es, but if light metal is used, the joint may be welded or otherwise strengthened. Spaced openings 52 are provided in the back 48 adjacent its upper edge and positioned to alinewith threaded openings 44 in the back panel 14 to receive attaching screws, 45. I]

screws 46 passing through holes 52 in the back and engaging threads Within the openings 44' formed in the back panel.

Openings 53 are also formed in the back 48 to aline with the lower pair of attaching openings 3. Washers 54 having a thickness equal to the thickness of the back 48 may be attached to the back surface of the back panel 54 in aline ment with the attachingopenings '43 so that the mounting willrest evenly against a flat'support. In" the type of mounting'illustrated'it will being, it may be formed from common materials by semi-skilled labor on ordinary shop equipment, which allows production of the mounting at low cost. Dimensional changes necessary to accommodate larger or smaller elements may also be made without the necessity of retooling or even changing the adjustments of the form with relatively clumsy tools. The absence of back and end walls allows free manipulation of tools, does not block out light, and greatly reduces the time required for assembly. The mounting and other assembly work may be completed prior to attachment of the cover, as there is no interconnection between the cover and wir ing or other mounted elements. In compliance with Section 4888 of the Revised StatutesI have described my invention in detail, but I do not Wish to be limited to the precise forms and embodiments set forth, as they are obviously capable of addition and modification without departure from the true scope and spirit of my invention.

Iclaim: v H I I 1. Ina mercury switch relay, a 2 section including a floor panel, a back panel, and a terminal panel, a mercury switch' relay and control circuit modifying means entirely supported by the 2 section above the floor panel, means below the floor panel interconnecting the relay and the control circuit modifying means, and a cover comprising a back, two end walls and a bottom adapted for removable attachment to the Z sec- 4 H tion, means for removably-attaching the cover.

to the 2 section and separate means for attaching the 2 section to a support, the cover being so constructed and arranged that only the interconnecting means below thefioor panel is completely enclosed when the cover is attached to the section, and easily accessible when the cover is removed. 7

2. In a mercury switch relay, a 2 section including a iloor panel, a back panel, and a-terminal panel, a mercury switch relay and control circuit modifying means attached to the 2 section above the floor panel, means interconnectingthe relay and the control circuit modifying means below the floor panel, and a cover including a back, two end walls and a bottom adapted for removable attachment to the back'panel, the

7 height of the back of the cover being greater than the depth of the terminal panel, the cover being so constructed and arranged that interconnecting means are completely enclosed when the cover is attached to the 2 section, and easily accessible when the cover is removed.

3. In a mercury switch relay, a Z section including a floorpanel, a back panel, and a terminal panel, a mercury switch relay and control circuit modifying means attached to the circuit above the floor panel, means below the floor panel interconnecting the relay and the control circuit modifying means, a cover including a back having a height greater than the depth of the terminal panel, two end walls having equal heights slightly less than the depth of the terminal panel, and a bottom having a length and width substantially equal to the length and width of the floor panel, and means for attachin the back of the cover to the back panel of the 2 section whereby the intercommunicating means are completely enclosed but readily accessible when the cover is removed.

4. In a mercury switch relay, a 2 section including three connected panels, a relay including a relay coil and means controlling energization of the coil, said relay and controlling means being supported exclusively by the Z section, a box-shaped cover having four walls defining an open side and front, said cover being so constructed and arranged that the open top and front of the cover are closed by the 2 section, and means for removably attaching the cover to the section, said means being independent of said relay and relay controlling means.

CARL H. LARSON. 

